We present diffraction-limited near-IR images in J, H and K of the nucleus of several AGNs obtained with PUEO, the Adaptive Optics system of CFHT. Thanks to the excellent sensitivity of the wavefront sensor, galactic nuclei as faint as mV equals 15 can be observed at a resolution of 0.12- 0.18 inch. IN NGC 1068, the Seyfert 2 prototype, the achieved resolution reveals: a) a belt which is most probably the trace of warm dust in the torus of gas and b) a S-shaped feature which is likely an extremely compact barred spiral structure. In Mkn 231, an Ultra Luminous galaxy, we resolve the very central peak in a bright point source with colors of an actual AGN and fainter source (B) at 0.15 arcsec north, with colors consistent with a giant HII complex of violent star formation. Arp 299, another Ultra- Luminous IR Galaxy, is a merger. Our K image reveals that none of the nuclei are un resolved; the presence of a QSO as the primary source of energy is thus dubious. We also discovered many super-clusters of newly formed stars with extremely high luminosities.